Electric meter.



No. 796,069. PATENTED AUG. 1, 1905.

' T. DUNCAN.

ELECTRIC METER.

APPLICATION FILED JULY 13,1 04.

@WQEQE delay. it is only necessary to clean the commutator UNITED STATESPATENT OFFICE.

Specification of Letters Patent.

Patented Aug. 1, 1905.

Application filed July 13, 1904- Serial No. 216,323.

specification.

' My invention relates to motor-meters employing collecting devicesincluding brushes, and finds wide application 1n connection with'wattmeters of the commutated type, and has for its object the provisionof an improved brush construction whereby the care and repair of thebrush-tips may be reduced to a minimum. As is well known, a great dealof injury is occasioned the brush-tips by reason of the sparking betweenthe same and the commutators arising upon the wear of the brushes, itbeing necessary on occasion to file off or otherwise smooth down thesurfaces of the brush-tips in order to have the meter resume itsoriginal accuracy and cease sparking. This repair ofthe brushes has tobe very correctly-clone requiring the services of an expert, on whichaccount many users of meters are compelled to return their meters to thefactory, occasioning considerable expense and In the device of mypresent invention with worn crocus cloth in the ordinary manner asrecommended by manufacturers, for I have provided a brush constructionincluding a tip which may be shifted in position with respect to thebrush and the commutator so that a new wearing-surface may be presentedto the commutator. The tip upon the brush is so mounted upon the brushthat it will remain in a position in which it is placed, so that newwearing-surfaces may be presented to the commutator. These brush-tipsare preferably of polyhedral formation, brushtips that are triangular,rectangular, or square answering well the purpose, though I do not wishto be limited to these shapes. These brush elements are desirablymounted to rotate upon axes that are transverse to the axis of thecommutator, the brush-arms being desirably formed to have as structuralparts thereof journal elements upon which the brush-tips are adapted torotate for the purpose stated.

I will explain my invention more fully by reference to the accompanyingdrawings, in -which Figure 1 is a view in elevation of an integratingwattmeter with electrical connections therefor diagrammatically shown.Fig. 2 is a perspective View of one form of brushtip. Fig. 3 is a viewof another form of brush-tip. Fig. I is a view of still another form ofbrush-tip. Fig. 5 is a plan view of a portion of the structureillustrated in Fig. 1. Fig. 6 is a front elevation showing a differentform of brush-tip than that shown in Fig. 1. Fig. 7 is a side elevationillustrating one mounting of brush-tip and brush. Fig. 8 is a sideelevation illustrating another brushtip mounting. Fig. 9 is another sideelevation illustrating still another brush-tip mounting.

Like parts are indicated by similar characters of reference throughoutthe different figures.

The. meter or measuring instrument illustrated has a current or seriesfield-winding sub-- divided into coils l 1, that are included in serieswith one of the mains 2, that are supplied from a source of directcurrent 3, translating devices, as lamps 4, being illustrated as a loadfor the circuit. The winding 5 is subdivided into coils thataremonntedupon a spindle 6 and which are included in bridge of the supply-mains 2by commutator-brushes7 engaglng acommutator 8, that is connected withthe coils of the winding 5, the windings 1 and 5 cooperating to producea wattmeter. A friction compensating coil 9 is provided in series withthe armature-coils and in series with extraneous artificial resistance10. The instrument being a recording instrument, a counter 11 is shownasbeing adapted for operation by the shaft 6. A damping-disk 12isprovided upon the lower end of the spindle and rotates within apermanent magnetic field, that may be furnished by the magnets 13. Thecommutatorbrushes 7 may have the major portion of their lengths formedof wire or strip metal, preferably of suflicient resiliency to enablethe brushes to exert requisite pressure upon the commutator.

In the construction shown in Figs. 5 and 7 l the brush-arms are providedwith reductions 1 upon which the brush-tips 15 are journaled, thesereduced ends 1A being rivet-headed to prevent the brush-tips fromslipping off. The brush-arms may be provided with any suitable blockmounting 16, having a clamping-screw 17 for holding the same inposition.

In the construction shown in Fig. 8 the journal 1a is of larger diameterto receive a screw 18, whose head holds the block or tip 15 in place.

In the construction shown in Fig. 9 there is no reduction 14;, the brushtip or block 15 being held against the end of the companion portion ofthe brush by a screw 19, the brush tip or block having the hole throughwhich the screw passes unthreaded, so that it may rotate freely upon thescrew. The material of which the brush-tips are made is preferablysilver, and the balance of the brush which supports the brush-tips ispreferably made of phosphor-bronze,though the material of which thebrush elements are made is not essential to a realization of theinvention. It will be apparent with what ease a free brush-surface willbe brought into engagement with the commutator, which may be done by anyone skilled or unskilled in meter adjustment.

I shall in the claims speak of the brush elements carrying the tips asthe stems. While I have shown specific ways for mounting the tips uponthese stems, whereby said tips are provided with axes of rotationtransverse to the axis of rotation of the meter-shaft and commutator, Ido not wish to be limited to the precise constructions illustrated; nordo I wish to be limited to the particular angle at which the axes ofrotation of the brush-tips are disposed transversely to the axis of thecommutator and shaft or spindle, though I prefer to have the axes of thebrush-tips at right angles to the axis of the commutator. The axes ofrotation of the blocks are generally parallel to the directions of thebrushstems.

I believe it to be new with me to provide brush elements, as the blocks15, that are rotatably mounted in bearings, whether said blocks or brushelements are mounted upon brush-stems or not.

I do not wish to be limited to a polyhedral formation of the brush-tips,nor to any particular number of surfaces in a multisur'faced brush-tip;nor do I wish to be limited to other specific characteristics ofconstructions illustrated, which may be modified without departing fromthe spirit of my invention; but,

Having thus described my invention, I claim as new and desire to secureby Letters Patent-- 1. A meter including a brush elementformed of a stemand a tip adjustable with respect to the same whereby a new tip-surfacemay be brought into contact, the tip and stem extending in the samedirection, substantially as described.

2. A meter including a brush element formed of a stem and a tipadjustable with respect to the same whereby a new tip-surface may bebrought into contact, said tip having an axis of rotation transverse tothe axis of rotation of the meter spindle, substantially as described.

3. A meter including a brush element formed of a stem and a tipadjustable with respect to the same whereby a new tip-surface may bebrought into contact, said tip having an axis of rotation at rightangles to the axis of rotation of the meter-spindle, substantially asdescribed.

L. A meter including a brush element formed of a stem and a tip ofpolyhedral formation adjustable with respect to the same whereby a newtip-surface may be brought into contact, the tip and stem extending inthe same direction, substantially as described.

5. A meter including a brush element formed of a stem and a tip ofpolyhedral formation adjustable with respect to the same whereby a newtip'surface may be brought into contact, said tip having an axis ofrotation transverse to the axis of rotation of the meterspindle,substantially as described.

6. A meter including a brush element formed of a stem and a tip ofpolyhedral formation adjustable with respect to the same whereby a newtip-surface may be brought into contact, said tip having an axis ofrotation at right angles to the axis of rotation of the meter-spindle,substantially as described.

7. A meter including a commutator for its armature, brushes engagingsaid commutator, each brush being formed of a stem and a tip adjustablewith respect to the same whereby a new tip-surface may be brought intocontact with the commutator, the tip and stem extending in the samedirection, substantially as described.

8. A meter including a commutator for its armature, brushes engagingsaid commutator, each brush being formed of a stem and a tip adjustablewith respect to the same whereby a new tip-surface may be brought intocontact with the commutator, said tip having an axis of rotationtransverse to the axis of retation of the meter-spindle, substantiallyas described.

9. A meter including a commutator for its armature, brushes engagingsaid commutator, each brush being formed of a stem and a tip adjustablewith respect to the same whereby a new tip-surface may be brought intocontact with the commutator, said tip having an axis of rotation atright angles to the axis of rotation of the meter-spindle, substantiallyas described.

10. A meter including a commutator for its armature, brushes engagingsaid commutator, each brush being formed of a stem and a tip ofpolyhedral formation adjustable with respect to the same whereby a newtip-surface may be brought into contact with the commu tator, the tipand stem extending in the same direction, substantially as described.

11. A meter including a commutator for its armature, brushes engagingsaid commutator, each brush being formed of a stem and a tip ofpolyhedral formation adjustable with respect to the same whereby a newtip-surface may be brought into contact with the commutator, said tiphaving an axis of rotation transverse to the axis of rotation of themeterspindle, substantially as described.

12. A meter including a commutator for its armature, brushes engagingsaid commutator, each brush being formed of a stem and a tip ofpolyhedral formation adjustable with respect to the same whereby a newtip-surface may be brought in contact with the commutator, said tiphaving an axis of rotation at right angles to the axis of rotation ofthe meter-spindle, substantially as described.

13. A meter including a brush element having a mounting permitting saidelement to be rotated to present a new surface, and a stem for the brushelement, the axis of rotation of said element being substantiallyparallel in direction to the stem, substantially as described.

14:. A commutated meter including brush elements each provided withmountings permitting said brush elements to be rotated to present newsurfaces to the commutator of the meter, and a stem-for the brushelement, the axis of rotation of said element being substantiallyparallel in direction to the stem, substantially as described.

15. A meter including a brush element having a mounting permitting saidelement to be rotated to present a new surface, the axis of rotationalforded by the brush-element mounting being transverse to the axis ofrotation of the meter spindle or shaft, substantially as described.

16. A commutated meter including brush elements each provided withmountings permitting said brush elements to be rotated to present newsurfaces to the commutator of the meter, the axes of rotation affordedby the brush-elementmountings being transverse to the axis of rotationof the meter spindle or shaft, substantially as described.

In Witness whereof I hereunto subscribe my name this 8th day of July, A.D. 1904.

THOMAS DUNCAN.

Witnesses:

MARSHALL F. HoLMEs, GEORGE L. (JRAGG.

